2020-10-27_PERMIT FILE - C1981035 (20)

Home Browse Search

Biological Assessment Federal Coal Lease Modification(COC-62920)and Federal Mine Permit(CO-0106A)Revision and Renewal campaign that replicated those populations across the landscape. Efforts to establish new populations were successful and populations are expected to meet recovery plan goals and become delisted. However, recent genetic work on museum and extant populations suggest that the true native greenback cutthroat trout occurs only in a single stream, Bear Creek, outside their historic range just west of Colorado Springs. Recent studies revealed that approximately 750 adult fish remain in Bear Creek and represent the last remaining individuals of the species. Aggressive recovery efforts have been implemented to replicate this population, with the first reintroduction in the wild occurring in August 2014. Life History Greenback cutthroat trout opportunistically feed on a wide range of prey organisms, but a large percentage of the diet is terrestrial insects. Greenbacks also feed on crustaceans (e.g., freshwater shrimp), aquatic insects, and small fish. Spawning typically occurs from late May to mid-July in higher elevations. Male cutthroats first spawn at age 2, and females mature a year later. Females build an egg pit in gravel generally 3 to 8 inches deep and 1 foot in diameter. A 10-inch female lays about 800 eggs. Larger fish of about 4 to 7 pounds lay up to 6,000 eggs. Habitat Greenback cutthroat trout occur in steep, cold-water mountain streams and lakes with clear, well-oxygenated water(Young 2009). Distribution and Status Until recently, delineations of subspecies of cutthroat trout in the southern Rocky Mountains were believed to follow geographic boundaries within several states, with greenback cutthroat trout on the east side of the Continental Divide and Colorado River cutthroat trout(O. C. pleuriticus) on the west side. Rio Grande cutthroat trout(O. c. virginalis) occur within the Rio Grande drainage; their range and genetic identity do not appear to be in question. Through the recent genetic (Metcalf et al. 2012) and meristic (Bestgen et al. 2013) studies that identified the native ranges of cutthroat in Colorado, we now know that greenbacks are native only to the headwaters of the South Platte River drainage in Colorado. Greenbacks were previously considered to be native also to the Arkansas River drainage (Behnke 1992). The original distribution of the greenback within the South Platte drainage is not precisely known due to its rapid decline in the 1800s. The loss of high-quality trout stream habitat through logging, livestock over-grazing, water diversions, mining, and municipal and industrial pollution is considered a contributing factor to the historical decline of the range of greenback. It is assumed that the original distribution included all mountain and foothill habitats of the drainage systems, including lower elevations than it occupies today (Behnke and Zarn 1976). The subspecies may have extended as far east as present day Greeley, Colorado, during the mid-1800s (WNTI 2007). July 2017 23